Epidemiological and microbiological characteristics of S. aureus pediatric infections in Colombia 2018-2021, a national multicenter study (Staphylored Colombia).

Background: Staphylococcus aureus infections are a significant cause of morbidity and mortality in pediatric populations worldwide. The Staphylo Research Network conducted an extensive study on pediatric patients across Colombia from 2018 to 2021. The aim of this study was to describe the epidemiological and microbiological characteristics of S. aureus in this patient group. Methods: We analyzed S. aureus isolates from WHONET-reporting centers. An "event" was a positive culture isolation in a previously negative individual after 2 weeks. We studied center characteristics, age distribution, infection type, and antibiotic susceptibilities, comparing methicillin sensitive (MSSA) and resistant S. aureus (MRSA) isolates. Results: Isolates from 20 centers across 7 Colombian cities were included. Most centers (80%) served both adults and children, with 55% offering oncology services and 85% having a PICU. We registered 8,157 S. aureus culture isolations from 5,384 events (3,345 MSSA and 1,961 MRSA) in 4,821 patients, with a median age of 5 years. Blood (26.2%) and skin/soft tissue (18.6%) were the most common infection sources. Most isolates per event remained susceptible to oxacillin (63.2%), clindamycin (94.3%), and TMP-SMX (98.3%). MRSA prevalence varied by city (<0.001), with slightly higher rates observed in exclusively pediatric hospitals. In contrast, the MRSA rate was somewhat lower in centers with Antimicrobial Stewardship Program (ASP). MRSA was predominantly isolated from osteoarticular infections and multiple foci, while MSSA was more frequently associated with recurrent infections compared to MRSA. Conclusions: This is the largest study of pediatric S. aureus infections in Colombia. We found MSSA predominance, but resistance have important regional variations. S. aureus remains susceptible to other commonly used antibiotics such as TMP-SMX and clindamycin. Ongoing monitoring of S. aureus infections is vital for understanding their behavior in children. Prospective studies within the Staphylored LATAM are underway for a more comprehensive clinical and genetic characterization.

Severe adenovirus infection outbreak in Colombia: Experience from a tertiary pediatric hospital in 2022. / Brote de adenovirus grave en Colombia: experiencia de un hospital pediátrico de tercer nivel en 2022

Introduction. During the SARS-CoV-2 pandemic, many countries experienced decreased respiratory virus circulation, followed by an out-of-season outbreak. In a pediatric hospital in Colombia, we observed a surge in severe adenovirus infections, leading to concerns about the impact of eased public health restrictions and immune debt in children under five years old. Objective. To describe the clinical characteristics of patients with severe adenovirus infection in a pediatric hospital in Colombia. Materials and methods. We reviewed the data of 227 patients with severe adenovirus infection at the Fundación Hospital Pediátrico La Misericordia. Results. A total of 196 patients were included in this study. The median age was two years, and 62% were male. Adenoviruses were isolated from all patients' samples. Ninetyseven percent were admitted to the pediatric intensive care unit, 94% required respiratory support, and the in-hospital lethality rate was 11%. Conclusion. In 2022, there was an outbreak of severe adenovirus infections, affecting mainly children under five years of age, with higher-than-usual mortality.

Introducción. Durante la pandemia por SARS-CoV-2, muchos países evidenciaron una disminución en la circulación de virus respiratorios, seguida por un brote fuera de la temporada esperada. En un hospital de Colombia, se observó un aumento en los casos de infección grave por adenovirus, lo cual generó preocupación sobre el impacto que tuvo la disminución de los cuidados establecidos durante pandemia y la posible deuda inmunológica en niños menores de cinco años. Objetivo. Describir las características clínicas de los pacientes con infección grave por adenovirus en un hospital pediátrico de Colombia. Materiales y métodos. Se revisaron 227 pacientes con infección grave por adenovirus en la Fundación Hospital Pediátrico La Misericordia, desde el 1° de enero hasta el 31 de diciembre de 2022. Resultados. El estudio incluyó 196 casos. La edad media de los pacientes fue de dos años y el 62 % eran de sexo masculino. Los adenovirus se aislaron a partir de las muestras de todos los pacientes. El 97 % de los pacientes ingresó a la unidad de cuidados intensivos, el 94 % requirió soporte ventilatorio y la tasa de mortalidad fue del 11 %. Conclusiones. En el 2022 hubo un brote de adenovirus que afectó principalmente a los niños menores de cinco años, con una mortalidad mayor a lo reportado con anterioridad en Colombia.

Use of multiplex PCR in pleural effusion: is it necessary to change the paradigm of culture-based methods?

The microbiological diagnosis of pleural effusion is based largely on classical microbiology methods, but these methods have a high rate of false negative results. Some previous studies have shown improved diagnostic performance for pathogens such as Streptococcus pneumoniae using molecular biology methods. We present the use of a multiplex PCR platform (BIOFIRE FILMARRAY Pneumonia Panel) for the aetiological diagnosis of pleural effusion in paediatric pneumonia. We present a case series of 17 pleural fluid samples that were processed by culture-based microbiology and molecular biology methods. Microbiological isolation was successful in four cases (25 %) through traditional culture methods. In contrast, the molecular biology panels allowed for detection in 16 out of 17 cases (94 %). The results from these panels led to a change in management for nine out of the 17 cases (52 %). This study found an increase in aetiological diagnosis in complicated pneumonia in children by using molecular biology methods, which led to a significant change in patient management.

Multinational prospective cohort study of incidence and risk factors for central line-associated bloodstream infections in ICUs of 8 Latin American countries.

BACKGROUND: Our objective was to identify central line (CL)-associated bloodstream infections (CLABSI) rates and risk factors in Latin-America. METHODS: From January 1, 2014 to February 10, 2022, we conducted a multinational multicenter prospective cohort study in 58 ICUs of 34 hospitals in 21 cities in 8 Latin American countries (Argentina, Brazil, Colombia, Costa Rica, Dominican Republic, Ecuador, Mexico, Panama). We applied multiple-logistic regression. Outcomes are shown as adjusted-odds ratios (aOR). RESULTS: About 29,385 patients were hospitalized during 92,956 days, acquired 400 CLABSIs, and pooled CLABSI rate was 4.30 CLABSIs per 1,000 CL-days. We analyzed following 10 variables: Gender, age, length of stay (LOS) before CLABSI acquisition, CL-days before CLABSI acquisition, CL-device utilization (DU) ratio, CL-type, tracheostomy use, hospitalization type, intensive care unit (ICU) type, and facility ownership, Following variables were independently associated with CLABSI: LOS before CLABSI acquisition, rising risk 3% daily (aOR=1.03;95%CI=1.02-1.04; P < .0001); number of CL-days before CLABSI acquisition, rising risk 4% per CL-day (aOR=1.04;95%CI=1.03-1.05; P < .0001); publicly-owned facility (aOR=2.33;95%CI=1.79-3.02; P < .0001). ICU with highest risk was medical-surgical (aOR=2.61;95%CI=1.41-4.81; P < .0001). CL with the highest risk were femoral (aOR=2.71;95%CI=1.61-4.55; P < .0001), and internal-jugular (aOR=2.62;95%CI=1.82-3.79; P < .0001). PICC (aOR=1.25;95%CI=0.63-2.51; P = .52) was not associated with CLABSI risk. CONCLUSIONS: Based on these findings it is suggested to focus on reducing LOS, CL-days, using PICC instead of femoral or internal-jugular; and implementing evidence-based CLABSI prevention recommendations.

First publication of endemic channels as part of a pediatric Antimicrobial Stewardship Program: when to turn on the alarms? Recommendations of a pediatric ASP program.

BACKGROUND: Pediatric Antimicrobial Stewardship Programs (ASP) consider DOT a fundamental measure to quantify the impact of ASP. Novel strategies have been described, but no endemic channels (EC) have been reported to compare antibiotic use within historical patterns. This report describes the process of constructing an EC and analyzing its interpretation. METHODS: This was a descriptive study of the construction, implementation, and analysis of EC. The median and quartile method, as well as the geometric mean (GM) and confidence interval (CI) methods using DOT for the last 4 years were used. ECs have also been elaborated on in critical services (PICU). RESULTS: GM and CI method seem to be more sensitive in identifying changes in antimicrobial use. Ceftriaxone increased its use starting in December 2021, reaching the warning zone in March 2022 in relation to increased cases of bacterial and complicated pneumonia. Piperacillin-tazobactam showed an important increase in PICU during the first 8 months of 2021, reaching the alert zone until August 2021; thereafter, its use decreased, and this variation was related to a modification in the presentation of complicated appendicitis during the COVID 19 pandemic restrictions. The use of ampicillin-sulbactam has increased since January 2022 because of a change in local guidelines regarding its use in appendicitis and peritonitis. The changes identified in each EC allowed ASP to take different conducts. CONCLUSION: EC allowed us to construct a new tool to measure ASP impact, internal comparison of antibiotic use facilitated taking timely interventions. EC could be useful for all pediatric and adult ASP.

Multinational Prospective Cohort Study of Mortality Risk Factors in 198 ICUs of 12 Latin American Countries over 24 Years: The Effects of Healthcare-Associated Infections.

BACKGROUND: The International Nosocomial Infection Control Consortium (INICC) has found a high ICU mortality rate in Latin America. METHODS: A prospective cohort study in 198 ICUs of 96 hospitals in 46 cities in 12 Latin American countries to identify mortality risk factors (RF), and data were analyzed using multiple logistic regression. RESULTS: Between 07/01/1998 and 02/12/2022, 71,685 patients, followed during 652,167 patient-days, acquired 4700 HAIs, and 10,890 died. We prospectively collected data of 16 variables. Following 11 independent mortality RFs were identified in multiple logistic regression: ventilator-associated pneumonia (VAP) acquisition (adjusted odds ratio [aOR] = 1.17; 95% CI: 1.06-1.30; p < 0.0001); catheter-associated urinary tract infection (CAUTI) acquisition (aOR = 1.34; 95% CI: 1.15-1.56; p < 0.0001); older age, rising risk 2% yearly (aOR = 1.02; 95% CI: 1.01-1.02; p < 0.0001); longer indwelling central line(CL)-days, rising risk 3% daily (aOR = 1.03; 95% CI: 1.02-1.03; p < 0.0001); longer indwelling urinary catheter(UC)-days, rising risk 1% daily (aOR = 1.01; 95% CI: 1.01-1.26; p < 0.0001); higher mechanical ventilation (MV) (aOR = 6.47; 95% CI: 5.96-7.03; p < 0.0001) and urinary catheter-utilization ratio (aOR = 1.19; 95% CI: 1.11-1.27; p < 0.0001); lower-middle level income country (aOR = 2.94; 95% CI: 2.10-4.12; p < 0.0001); private (aOR = 1.50; 95% CI: 1.27-1.77; p < 0.0001) or public hospital (aOR = 1.47; 95% CI: 1.24-1.74; p < 0.0001) compared with university hospitals; medical hospitalization instead of surgical (aOR = 1.67; 95% CI: 1.59-1.75; p < 0.0001); neurologic ICU (aOR = 4.48; 95% CI: 2.68-7.50; p < 0.0001); adult oncology ICU (aOR = 3.48; 95% CI: 2.14-5.65; p < 0.0001); and others. CONCLUSION: Some of the identified mortality RFs are unlikely to change, such as the income level of the country, facility ownership, hospitalization type, ICU type, and age. But some of the mortality RFs we found can be changed, and efforts should be made to reduce CL-days, UC-days, MV-utilization ratio, UC-utilization ratio, and lower VAPs and CAUTI rates.

Epidemiological characteristics and serotype distribution of culture-confirmed pediatric pneumococcal pneumonia before and after PCV 10 introduction, a multicenter study in Bogota, Colombia, 2008-2019.

BACKGROUND: Pneumococcal conjugate vaccines (PCVs) have decreased pneumonia in children. Colombia introduced mass vaccination with PCV10 in 2012. METHODS: Cases of pneumococcal pneumonia from 10 hospitals were included. Two periods were compared: pre-PCV10: 2008-2011 and post-PCV10: 2014-2019. The objective was to compare epidemiological and clinical characteristics before and after PCV10 vaccination. RESULTS: A total of 370 cases were included. Serotypes 1 (15, 11.2%) and 14 (33, 24.6%) were the most frequent in the pre-PCV10 period, with only 4 (3%) cases of serotype 19A and 1 case (0.7%) serotype 3. From the pre-PCV10 period to the post-PCV10 period, cases of serotypes 1 (6, 3.1%) and 14 (1, 7.8%) decreased, while cases of serotypes 19A (58, 30.2%), serotype 3 (32, 16.7%) and 6A (7, 3.6%) increased (p < 0.001); complicated pneumonia (CP) increased significantly (13.4% to 31.8%) (p < 0.001); hospitalizations increased from 8 (5.5-15) to 12 (7-22) days (p < 0.001); and the frequency of PICU admission increased from 32.8% to 51.6% (p = 0.001). The use of ampicillin-sulbactam (0.7% to 24%) and ceftriaxone/clindamycin (0.7% to 5.7%) increased in the post-PCV10 period. The duration of empirical antibiotic treatment was 7 (4-11) days in the pre-PCV10 period and increased to 10 (6-17) days (p < 0.001) in the post-PCV10 period. Lethality showed a slight nonsignificant increase (7.5% vs. 9.9%; p = 0.57) in the post-PCV10 period. CONCLUSIONS: PCV10 significantly decreased cases of serotypes 1 and 14, with an increase in cases of serotypes 19A, 3 and 6A, which were the predominant serotypes and had greater severity (e.g., admission to the PICU, CP and more resistance, with an increase in the use of broad-spectrum antibiotics and longer hospitalization) and subsequently included in PCV13. Current data support national and regional evidence on the importance of replacing PCV10 with a higher valence that includes 19A, such as PCV13, with the aim of reducing circulation, particularly of this serotype.

Contribution of non-selective membrane channels and receptors in epilepsy.

Overcoming refractory epilepsy's resistance to the combination of antiepileptic drugs (AED), mitigating side effects, and preventing sudden unexpected death in epilepsy are critical goals for therapy of this disorder. Current therapeutic strategies are based primarily on neurocentric mechanisms, overlooking the participation of astrocytes and microglia in the pathophysiology of epilepsy. This review is focused on a set of non-selective membrane channels (permeable to ions and small molecules), including channels and ionotropic receptors of neurons, astrocytes, and microglia, such as: the hemichannels formed by Cx43 and Panx1; the purinergic P2X7 receptors; the transient receptor potential vanilloid (TRPV1 and TRPV4) channels; calcium homeostasis modulators (CALHMs); transient receptor potential canonical (TRPC) channels; transient receptor potential melastatin (TRPM) channels; voltage-dependent anion channels (VDACs) and volume-regulated anion channels (VRACs), which all have in common being activated by epileptic activity and the capacity to exacerbate seizure intensity. Specifically, we highlight evidence for the activation of these channels/receptors during epilepsy including neuroinflammation and oxidative stress, discuss signaling pathways and feedback mechanisms, and propose the functions of each of them in acute and chronic epilepsy. Studying the role of these non-selective membrane channels in epilepsy and identifying appropriate blockers for one or more of them could provide complementary therapies to better alleviate the disease.

Long-term effects of stress resilience: Hippocampal neuroinflammation and behavioral approach in male rats.

Resilience to stress is the ability to quickly adapt to adversity. There is evidence that exposure to prolonged stress triggers neuroinflammation what produces individual differences in stress vulnerability. However, the relationship between stress resilience, neuroinflammation, and depressive-like behaviors remains unknown. The aim of this study was to analyze the long-term effects of social defeat stress (SDS) on neuroinflammation in the hippocampus and depressive-like behaviors. Male rats were subjected to the SDS paradigm. Social interaction was analyzed 1 and 2 weeks after ending the SDS to determine which animals were susceptible or resilient to stress. Neuroinflammation markers glial fibrillary acidic protein, ionized calcium-binding adaptor molecule 1, and elevated membrane permeability in astrocytes and microglia, as well as depressive-like behaviors in the sucrose preference test and forced swim test were evaluated in all rats. One week after SDS, resilient rats increased their sucrose preference, and time spent in the floating behavior decreased in the forced swim test compared to susceptible rats. Surprisingly, resilient rats became susceptible to stress, and presented neuroinflammation 2 weeks after SDS. These findings suggest that SDS-induced hippocampal neuroinflammation persists in post-stress stages, regardless of whether rats were initially resilient or not. Our study opens a new approach to understanding the neurobiology of stress resilience.

ADENOSINE DEAMINASE ACTIVITY AND SERUM C-REACTIVE PROTEIN AS PROGNOSTIC MARKERS OF CHAGAS DISEASE SEVERITY.

Chagas disease is a public health problem worldwide. The availability of diagnostic tools to predict the development of chronic Chagas cardiomyopathy is crucial to reduce morbidity and mortality. Here we analyze the prognostic value of adenosine deaminase serum activity (ADA) and C-reactive protein serum levels (CRP) in chagasic individuals. One hundred and ten individuals, 28 healthy and 82 chagasic patients were divided according to disease severity in phase I (n = 35), II (n = 29), and III (n = 18). A complete medical history, 12-lead electrocardiogram, chest X-ray, and M-mode echocardiogram were performed on each individual. Diagnosis of Chagas disease was confirmed by ELISA and MABA using recombinant antigens; ADA was determined spectrophotometrically and CRP by ELISA. The results have shown that CRP and ADA increased linearly in relation to disease phase, CRP being significantly higher in phase III and ADA at all phases. Also, CRP and ADA were positively correlated with echocardiographic parameters of cardiac remodeling and with electrocardiographic abnormalities, and negatively with ejection fraction. CRP and ADA were higher in patients with cardiothoracic index ≥ 50%, while ADA was higher in patients with ventricular repolarization disturbances. Finally, CRP was positively correlated with ADA. In conclusion, ADA and CRP are prognostic markers of cardiac dysfunction and remodeling in Chagas disease.

ADENOSINE DEAMINASE ACTIVITY AND SERUM C-REACTIVE PROTEIN AS PROGNOSTIC MARKERS OF CHAGAS DISEASE SEVERITY / Atividade da adenosina deaminase e níveis de proteina C reativa sérica como marcadores de gravidade na doença de Chagas

SUMMARY Chagas disease is a public health problem worldwide. The availability of diagnostic tools to predict the development of chronic Chagas cardiomyopathy is crucial to reduce morbidity and mortality. Here we analyze the prognostic value of adenosine deaminase serum activity (ADA) and C-reactive protein serum levels (CRP) in chagasic individuals. One hundred and ten individuals, 28 healthy and 82 chagasic patients were divided according to disease severity in phase I (n = 35), II (n = 29), and III (n = 18). A complete medical history, 12-lead electrocardiogram, chest X-ray, and M-mode echocardiogram were performed on each individual. Diagnosis of Chagas disease was confirmed by ELISA and MABA using recombinant antigens; ADA was determined spectrophotometrically and CRP by ELISA. The results have shown that CRP and ADA increased linearly in relation to disease phase, CRP being significantly higher in phase III and ADA at all phases. Also, CRP and ADA were positively correlated with echocardiographic parameters of cardiac remodeling and with electrocardiographic abnormalities, and negatively with ejection fraction. CRP and ADA were higher in patients with cardiothoracic index ≥ 50%, while ADA was higher in patients with ventricular repolarization disturbances. Finally, CRP was positively correlated with ADA. In conclusion, ADA and CRP are prognostic markers of cardiac dysfunction and remodeling in Chagas disease.

Introdução e objetivo . A Doença de Chagas é um problema de saúde pública mundial. A disponibilidade de ferramentas diagnósticas para prever o desenvolvimento de miocardiopatia chagásica crônica é fundamental para reduzir a morbidade e a mortalidade. Aqui estudamos o valor prognóstico da atividade sérica da adenosina deaminase (ADA) e dos níveis de proteína C reativa (PCR) em indivíduos chagásicos. Métodos : 110 indivíduos: 28 saudáveis e 82 pacientes chagásicos foram divididos de acordo com a gravidade da doença em fase I (n = 35), II (n = 29) e III (n = 18). Para cada indivíduo foram feitos uma história médica, eletrocardiograma, radiografia de tórax e ecocardiografía transtorácica. O diagnóstico de Chagas foi confirmado por ELISA e MABA utilizando antígenos recombinantes, a atividade sérica da enzima ADA foi determinada por espectrofotometria, e os níveis séricos de PCR por ELISA. Resultados : os níveis de PCR e da atividade da ADA aumentaram linearmente em relação à fase da doença, sendo a PCR significativamente maior na fase III, e a ADA em todas as fases. Além disso, PCR e ADA foram correlacionados positivamente com parâmetros ecocardiográficos de remodelamento cardíaco e alterações eletrocardiográficas, e negativamente com a fração de ejeção. PCR e ADA foram mais elevadas em pacientes com índice cardiotorácico ≥ 50%, enquanto que a ADA foi maior em pacientes com alterações da repolarização ventricular. Finalmente, os níveis de PCR foram correlacionados positivamente com a atividade da ADA. Conclusão : ADA e PCR são marcadores prognósticos de disfunção e remodelamento cardíaco na Doença de Chagas, e devem ser incluídos na avaliação e acompanhamento dos pacientes.

Successive Oral Immunizations Against Piscirickettsia Salmonis and Infectious Salmon Anemia Virus are Required to Maintain a Long-Term Protection in Farmed Salmonids.

Currently, there is a growing demand to determine the protective status of vaccinated fish in order to prevent diseases outbreaks. A set of different parameters that include the infectious and immunological status of vaccinated salmonids from 622 Chilean farms were analyzed during 2011-2014. The aim of this study was to optimize the vaccination program of these centers through the determination of the protective state of vaccinated fish using oral immunizations. This state was determined from the association of the concentration of the immunoglobulin M (IgM) in the serum and the mortality rate of vaccinated fish. Salmonids were vaccinated with different commercial mono- or polyvalent vaccines against salmonid rickettsial septicemia (SRS) and infectious salmon anemia (ISA), first by the intraperitoneal injection of oil-adjuvanted antigens and then by the stimulation of mucosal immunity using oral vaccines as a booster vaccination. The results showed that high levels of specific IgM antibodies were observed after injectable vaccination, reaching a maximum concentration at 600-800 degree-days. Similar levels of antibodies were observed when oral immunizations were administrated. The high concentration of antibodies [above 2750 ng/mL for ISA virus (ISAv) and 3500 ng/mL for SRS] was maintained for a period of 800 degree-days after each vaccination procedure. In this regard, oral immunizations maintained a long-term high concentration of anti-SRS and anti-ISAv specific IgM antibodies. When the concentration of antibodies decreased below 2000 pg/mL, a window of susceptibility to SRS infection was observed in the farm, suggesting a close association between antibody levels and fish protective status. These results demonstrated that, in the field, several oral immunizations are essential to uphold a high level of specific anti-pathogens antibodies and, therefore, the protective status during the whole productive cycle.

Prevalence of Trypanosoma cruzi antibodies and inflammatory markers in uncompensated heart failure / Prevalência de anticorpos anti-Trypanosoma cruzi e marcadores inflamatórios em pacientes com insuficiência cardíaca descompensada

INTRODUCTION: Heart failure (HF) represents the final stage of chronic chagasic cardiomyopathy (CChC). The diagnosis of CChC is based on the demonstration of anti-Trypanosoma cruzi antibodies (aTcAg) and clinical and epidemiological data. In Venezuela, there are no data about the prevalence of chagasic HF. The aim of this study was to determine the epidemiological, clinical, and inflammatory risk factors associated with seronegative or seropositive HF patients. METHODS: We performed a cross-sectional study in the Venezuelan central-west states among a healthy rural population and in patients admitted to the emergency room with uncompensated HF. RESULTS: The seroprevalence rates of Trypanosoma cruzi antibodies were 11.2 percent and 40.1 percent in the healthy population and in HF patients, respectively. Seropositivity in healthy individuals was associated with age, knowledge on triatomine vectors, and having seen wild reservoirs in the house; in HF patients, with contact with the vector and previous clinical diagnosis of Chagas' disease; and in both groups taken together, with age, knowledge on triatomines, and HF. Seropositive patients had prolonged QRS, decreased ejection fraction, and high serum magnesium, all significant as compared with HF seronegative cases. Left atrium enlargement and ventricular hypertrophy were most frequently observed in HF seronegative patients. CRP, IL6, ILβ1, IL2, and FNTα were elevated in 94.5 percent, 48 percent, 17.8 percent, 13.7 percent, and 6.9 percent of HF patients, respectively, but only IL2 levels were associated with chagasic HF. CONCLUSIONS: There is a high prevalence of aTcAg in HF patients from the central-west region of Venezuela, and their epidemiological, clinical, and inflammatory features are discreetly different as compared with those of seronegative cases.

INTRODUÇÃO: A insuficiência cardíaca (IC) representa o estágio final da cardiopatia chagásica crônica (CChC). O diagnóstico de CChC é baseado na demonstração de anticorpos anti-Trypanosoma cruzi (AgTc), dados clínicos e epidemiológicos. Na Venezuela, não há informação sobre a prevalência da IC chagásica. O objetivo deste estudo foi determinar fatores de risco epidemiológicos, clínicos e inflamatórios associados à IC chagásica. MÉTODOS: Realizamos um estudo prospectivo transversal em estados do centro-oeste da Venezuela em uma população rural saudável e em pacientes com IC descompensada. RESULTADOS: A soroprevalência de AgTc mostrou valores de 11,2 por cento e 40,1 por cento na população saudável e em pacientes com IC, respectivamente. A soropositividade de indivíduos sadios se associou com a idade, conhecimento de vetores e a observação de reservatórios silvestres na habitação. Em pacientes com IC, estavam relacionados ao contato com o vetor e ao diagnóstico clínico prévio de doença de Chagas. Em ambos os grupos juntos, a soropositividade foi associada com idade, conhecimento do vetor e com IC. Os pacientes soropositivos apresentavam prolongamento do intervalo QRS, fração de ejeção diminuída e magnésio sérico elevado. Aumento atrial esquerdo e hipertrofia ventricular foram as mais frequentemente observadas em pacientes com IC soronegativos. PCR, IL6, ILβ1, IL2 e FNTα foram elevados em 94,5, 48, 17,8, 13,7 e em 6,9 por cento dos pacientes com IC, respectivamente; os níveis de IL-2 foram associados com IC chagásica. CONCLUSÕES: Uma alta prevalência de AgTc foi observada em pacientes com IC na região centro-oeste da Venezuela, cujos aspectos epidemiológicos, clínicos e inflamatórios são discretamente diferentes dos soronegativos.

Prevalence of Trypanosoma cruzi antibodies and inflammatory markers in uncompensated heart failure.

INTRODUCTION: Heart failure (HF) represents the final stage of chronic chagasic cardiomyopathy (CChC). The diagnosis of CChC is based on the demonstration of anti-Trypanosoma cruzi antibodies (aTcAg) and clinical and epidemiological data. In Venezuela, there are no data about the prevalence of chagasic HF. The aim of this study was to determine the epidemiological, clinical, and inflammatory risk factors associated with seronegative or seropositive HF patients. METHODS: We performed a cross-sectional study in the Venezuelan central-west states among a healthy rural population and in patients admitted to the emergency room with uncompensated HF. RESULTS: The seroprevalence rates of Trypanosoma cruzi antibodies were 11.2% and 40.1% in the healthy population and in HF patients, respectively. Seropositivity in healthy individuals was associated with age, knowledge on triatomine vectors, and having seen wild reservoirs in the house; in HF patients, with contact with the vector and previous clinical diagnosis of Chagas' disease; and in both groups taken together, with age, knowledge on triatomines, and HF. Seropositive patients had prolonged QRS, decreased ejection fraction, and high serum magnesium, all significant as compared with HF seronegative cases. Left atrium enlargement and ventricular hypertrophy were most frequently observed in HF seronegative patients. CRP, IL6, ILß1, IL2, and FNTα were elevated in 94.5%, 48%, 17.8%, 13.7%, and 6.9% of HF patients, respectively, but only IL2 levels were associated with chagasic HF. CONCLUSIONS: There is a high prevalence of aTcAg in HF patients from the central-west region of Venezuela, and their epidemiological, clinical, and inflammatory features are discreetly different as compared with those of seronegative cases.

Relevance of Arg457 for the nucleotide affinity of Saccharomyces cerevisiae phosphoenolpyruvate carboxykinase.

Phosphoenolpyruvate carboxykinases catalyze one of the first steps in the biosynthesis of glucose and depending on the enzyme origin, preferentially use adenine or guanine nucleotides as substrates. The Saccharomyces cerevisiae enzyme has a marked preference for ADP (or ATP) over other nucleotides. Homology models of the enzyme in complex with ADP or ATP show that the guanidinium group of Arg457 is close to the adenine base, suggesting that this group might be involved in the stabilization of the nucleotide substrate. To evaluate this we have performed the mutation Arg457Met, replacing the positively charged guanidinium group by a neutral residue. The mutated enzyme retained the structural characteristics of the wild-type protein. Fluorescence titration experiments showed that mutation causes a loss of 1.7 kcal mol(-1) in the binding affinity of the enzyme for ADPMn. Similarly, kinetic analyses of the mutated enzyme showed 50-fold increase in K(m) for ADPMn, with minor alterations in the other kinetic parameters. These results show that Arg457 is an important factor for nucleotide binding by S. cerevisiae PEP carboxykinase.

Kinetic and molecular evidences that human cardiac muscle express non-M2 muscarinic receptor subtypes that are able to interact themselves.

In heart tissue five isoforms of the muscarinic acetylcholine receptor (mAChR) have been identified, designated m1-m5, of which only M1, M2 and M3 have functional evidences for their role in cardiac physiology. The present study was designed to explore the diversity of mAChR subtypes in human hearts and determine whether these subtypes are able to interact themselves. Expression of mRNAs encoding all five subtypes was readily detected by RT-PCR reaction in both atrial (A) and ventricle (V) samples. Immunoblotting, MABA and ELISA with subtype-specific antibodies confirmed the presence of M1, M2, M3, M4 and M5 proteins in membrane preparations from both A and V. Kinetic characterization using [(3)H]-QNB shown: (1) atrium had greater B(max) than did the ventricle, (2) [(3)H]-QNB behave as an allosteric modulator, inducing cooperativity at high and disclosing heterogeneity at low concentrations, (3) heterogenity was observed in pirenzepine, biperiden and tropicamide competition curves, being the high affinity sites compatible with M1 and M4 muscarinic receptor subtypes and (4) methoctramine competition curves in presence of selective muscarinic receptor subtypes antagonist displayed heterogeneity profile still maintaining cooperativity (n(H)>1), indicating muscarinic receptors subtypes are able to form homo- and hetero-oligomers. In conclusion, our results provide molecular and kinetic evidence for the presence of multiple subtypes of mAChR in human hearts, which are able to undergo discrete transitions from a non-cooperative kinetics of non-interacting monomers to a cooperative kinetics of interacting oligomers.